Monday, May 10, 2010

A company that won a NASA prize for beaming power to a climber in a space-elevator competition is targeting unmanned aircraft as an initial application for its laser-based technology.
LaserMotive says power beaming could extend the endurance of electrically powered UAVs. The company plans to fly a small internally funded demonstrator by year’s end.
The Seattle-based company has had discussions with some UAV manufacturers, and could have working prototypes of the system available within 18 months, says Tom Nugent, president and co-founder.
The demonstrator, based on a small unmanned helicopter, will reuse the hardware from the 2009 Space Elevator Games, where LaserMotive won a $900,000 prize for powering a robot up a kilometer-long cable.
The system would route power from arrays of near-infrared laser diodes to a beam director that would track the UAV and keep the beam pointed at photovoltaic cells on the airframe. These would convert the laser light to electricity to power the UAV or recharge its batteries to extend endurance.
LaserMotive foresees three possible applications: stationary platforms, such as a high-altitude airship, that would operate indefinitely under constant laser power: extended-endurance aircraft that would operate away from the beaming station, returning to recharge when the batteries run low; and laser-powered UAVs that would stay on patrol within line-of-sight of the beaming station, which also could be mobile.
Because heavier unmanned aircraft are gasoline or kerosene fueled, the company initially is targeting makers of small electric-powered UAVs, Nugent says. Extending their endurance would reduce the number of vehicles and manpower required, he says.
To deliver 1kW of DC power to a UAV with current technology would require a 2kW beam and 4kW of input power to the laser diodes, but some small vehicles need only 100-200W, Nugent says. Laser beams of a kilowatt and higher will require development of safety systems to ensure the beam is switched off when not pointing at the vehicle, he says.
LaserMotive also is looking at other applications, including beaming power to deployed ground sensors and remote communications-relay stations. Laser power beaming could also be used in disaster-relief operations, he says.By: Graham Warwick(AviationWeek)Photo: Insitu